Generally, a robot uses infrared positioning technology to locate its own position. However, because infrared rays have a limited transmitting range and the infrared rays are easily blocked by an object, when the robot is at a position far away from a charging base, the robot may be unable to detect infrared rays transmitted by the charging base. Such that the robot cannot automatically move back to the charging base for recharging because the relative position of the charging base cannot be actually positioned by the robot.